When a (meth)acrylic polymer having a crosslinkable functional group, for example a polymer having a (meth)acryloyl group and a polymer having an alkenyl group are subjected to a crosslinking reaction in order to obtain rubber-like cured products, the former requires irradiation with an active energy ray such as UV, electron beam or heating after addition of a radical initiator (Non-patent Document 1) and the latter requires heating after addition of a hydrosilyl compound/hydrosilylation catalyst (Patent Document 1), because their curing at ordinary temperature is difficult. In applications to sealing materials, adhesives, FIPG (Formed In Place Gaskets) and the like where curing at ordinary temperature is required, polymers having crosslinkable silyl groups capable of curing with moisture at ordinary temperature are frequently mainly used (Patent Document 2). In the case of a polymer containing a hydrolysable silyl group, its crosslinking reaction is in the form of condensation reaction, so the resulting rubber-like cured product may undergo curing shrinkage (Patent Document 3), and when such a polymer is cured after being blended with another reactive resin represented by epoxy resin, there is a difference in the form of crosslinking reaction therebetween, thus bringing about problems such as deterioration in compatibility, insufficient expression of mechanical properties, and the like.
The polymer containing a hydrolysable silyl group is compounded with a curing catalyst such as an organometallic compound, particularly an organotin compound, and is thus also problematic from an environmental point of view (Patent Document 4).
A crosslinking reaction utilizing a Michael addition reaction of an amine compound to a carbon-carbon double bond is considered useful as a crosslinking reaction for solving the problem as described above.
For the crosslinking reaction utilizing Michael addition, there are proposed coating curable compositions with improvements in coating appearance and weather resistance, which contains a component having an α, β-unsaturated carboxylic acid, an active methylene group, and a Michael addition acceleration catalyst (Patent Document and Patent Document 6), an aqueous coating compositions with an improvement in weather resistance, which contains an acrylic polymer having an active methylene group in its molecule, an ethylenically unsaturated group and a Michael addition acceleration catalyst (Patent Document 7), and the like, but most of these prior techniques are related to application to coatings.
Up to now, there has been no report of an invention wherein the Michael addition reaction between a vinyl-based polymer having a double bond in its molecule, particularly at its molecular terminus, and an amine compound is utilized to give a rubber-like cured product excellent in oil resistance, heat resistance and weather resistance.    Patent Document 1: Japanese Patent Laying-Open No. 11-080570    Patent Document 2: Japanese Patent Laying-Open No. 11-130931    Patent Document 3: Japanese Patent Laying-Open No. 11-349827    Patent Document 4: Japanese Patent Laying-Open No. 2003-246861    Patent Document 5: Japanese Patent Laying-Open No. 8-283626    Patent Document 6: Japanese Patent Laying-Open No. 10-45993    Patent Document 7: Japanese Patent Laying-Open No. 9-310042    Non-patent Document 1: UV•EB Koka Zairyo (UV/EB Curable Material) supervised by Maiho Tabata and published on Dec. 28, 1992, by CMC Publishing CO., LTD.